Zonal trabecular uni-compartmental tibial plateau containing zirconium-niobium alloy on oxidation layer and preparation method thereof

ABSTRACT

The present invention discloses a zonal trabecular uni-compartmental tibial plateau containing zirconium-niobium alloy on oxidation layer and preparation method, including following steps: using zirconium niobium alloy powder as raw material, conducting a 3D printing for one-piece molding to obtain an intermediate product of the uni-compartmental tibial plateau, performing hot isostatic pressing and cryogenic oxidation to obtain the uni-compartmental tibial plateau; the lower surface of the semi-tibial plateau support and the surface of the keel plate are both provided with a bone trabeculae; the zonal trabecular uni-compartmental tibial plateau adopts the structure of arranging step distributed bone trabeculaes which can reduce the fretting wear of the interface between the prosthesis and the bone, and reduce the stress shielding effect of the prosthesis on the bone tissue, homogenize the stress of the tibial plateau bone tissue, and improve the initial stability and long-term stability of the uni-compartmental tibial plateau.

CROSS-REFERENCE TO RELATED APPLICATIONS

This Application is a national stage application of PCT/CN2021/101285.This application claims priorities from PCT Application No.PCT/CN2021/101285, filed Jun. 21, 2021, and from the Chinese patentapplication 202011195196.6 filed Oct. 30, 2020, the content of which areincorporated herein in the entirety by reference.

TECHNICAL FIELD

The present disclosure relates to the technical field of artificialjoint, especially the zonal trabecular uni-compartmental tibial plateaucontaining zirconium-niobium alloy on oxidation layer and preparationmethod thereof.

BACKGROUND TECHNOLOGY

Uni-compartmental knee prosthesis is used for surface replacement ofunilateral diseased compartment of knee joint. It has thecharacteristics of small surgical incision, less intraoperativeosteotomy and preservation of knee ligament structure. Therefore, it canrecover quickly after single condylar replacement and preserve thenormal movement and proprioception of knee joint.

At present, Uni-compartmental knee prosthesis can be divided into bonecement fixation and biological fixation according to different fixationmethods. Bone cement fixation is easy to cause clinical bone cementsyndrome, such as bone cement fragmentation, thermal burn and infectionto bone tissue. Meanwhile, it is easy to misjudge the clinicalphysiological transparent line, mistakenly think that the prosthesis isloose, resulting in a large number of unnecessary revision afteroperation.

Biological uni-compartmental knee prosthesis can effectively chime theinterface between bone tissue and prosthesis and avoid the defectscaused by bone cement fixation. At present, biological uni-compartmentalknee prosthesis is mostly processed with double coating (e.g. titaniummicropore & HA coating), which has problems such as coating falling offand uneven coating thickness. Moreover, the main reason for the failureof artificial joint replacement is the loosening of the prosthesis. Thestress shielding caused by the huge stiffness mismatch between theprosthesis and bone will cause the bone remodeling around the prosthesisand lead to the loosening of the prosthesis. The matrix portion of theexisting biological uni-compartmental knee prosthesis is still a solidstructure, and its elastic modulus is much greater than that of bonetissue, which will greatly increase the stress shielding effect betweenthe prosthesis and bone interface and then reduce the formation ofosteoblasts, and finally lead to prosthesis loosening.

The uniform trabecular uni-compartmental knee prosthesis made of 3Dprinting can reduce the stress shielding effect to a certain extent,which can improve the long-term survival rate of the prosthesis.However, due to the mechanical differences of bone tissue in differentregions and the differences of mechanical environment of prosthesis indifferent regions, these differences will cause the non-uniformity offixation although using the uniform trabecular uni-compartmental kneeprosthesis, which will cause a certain impact on the long-term stabilityof prosthesis and increase the risk of failure.

Zirconium-niobium alloy has been gradually used in the field of medicaldevices for its excellent corrosion resistance, mechanical propertiesand good biocompatibility. Zirconium-niobium alloy can react with N, C,O or other elements to form a hard ceramic layer on the surface. It hasexcellent wear resistance and low wear rate, which can reduce the wearof soft materials, that is, it has excellent wear resistance of jointarticular surface. Moreover, the ceramic layer can reduce the release ofmetal ions and has excellent biocompatibility, that is, excellentbiocompatibility at the osseointegration interface. The low wear rate ofthe articular surface is combined organically with the osseointegrationinterface (trabecula), which has excellent bone ingrowth performance,enabling the prosthesis to achieve the advantages of both interfaces atthe same time. However, there is no existing report on the preparationof zonal trabecular uni-compartmental tibial plateau containingzirconium-niobium alloy on oxidation layer.

3D printing technology, as an additive manufacturing technology, breaksthrough the manufacturing process-oriented product design concepts, andrealizes the performance-oriented product design concept, that is, tosolve the problem of complex parts that are difficult to form as awhole, and to reduce the waste of raw materials and energy caused bymachining and manufacturing. However, the 3D printing products are proneto problems such as uneven microstructure and internal defects, and poormechanical properties. The failure of powder fusion in part oftrabecular structure also results in poor mechanical properties.

In view of the shortcomings of the prior art, people skilled in the artin this technical field are devoted to developing zonal trabecularuni-compartmental tibial plateau containing zirconium-niobium alloy withoxidation layer which has excellent mechanical properties and realizingthe advantages of two interfaces, so as to improve the fixationreliability of uni-compartmental tibial plateau and the initial andlong-term stability of prosthesis.

SUMMARY OF THE DISCLOSURE

One of the objectives of the present disclosure is to overcome thedeficiencies of the existing technology to provide zonal trabecularuni-compartmental tibial plateau containing zirconium-niobium alloy onoxidation layer.

The second objective of the present disclosure is to provide apreparation method of the zonal trabecular uni-compartmental tibialplateau containing zirconium-niobium alloy on oxidation layer.

The technical scheme of the present disclosure is outlined as follows:

The preparation method of the zonal trabecular uni-compartmental tibialplateau containing zirconium-niobium alloy on oxidation layer includesthe following steps:

-   1) Using zirconium-niobium alloy powder as a raw material,    conducting a 3D printing for one-piece molding, and obtaining a    first intermediate product of the zonal trabecular uni-compartmental    tibial plateau containing zirconium-niobium alloy on oxidation    layer, putting the first intermediate product into a Sinter-HIP    furnace, heating to 1250° C.-1400° C. under inert gas protection,    and placing at a constant pressure of 140 MPa to 180 MPa for 1 h to    3 h, and reducing to a normal pressure, cooling to below 200° C.    with the furnace, taking it out, and obtaining a second intermediate    product;-   2) Putting the second intermediate product into a programmed    thermostat, cooling to -80° C. to -120° C. at a rate of 1° C./min,    keeping it at a constant temperature for 5 h to10 h, and taking it    out of the programmed thermostat; and putting it into a liquid    nitrogen for 16 h to 36 h, and adjusting the temperature to a room    temperature so as to obtain a third intermediate product;-   3) Putting the third intermediate product in a programmed    thermostat, cooling to -80° C. to -120° C. at a rate of 1° C./min,    and placing it at a constant temperature for 5 h to10 h, taking it    out of the programmed thermostat, and putting it into the liquid    nitrogen for 16 h to 36 h, and adjusting the temperature to room    temperature so as to obtain a fourth intermediate product;-   4) Machining, finishing, polishing, cleaning, and drying the fourth    intermediate product, and obtaining a fifth intermediate product,    where the upper surface roughness of the fifth intermediate    semi-tibial plateau support is Ra≤0.050 µm;-   5) Putting the fifth intermediate product into a tube furnace,    introducing the normal-pressure inert gas containing 5% to 15% of    oxygen in percentage by mass, heating to 500° C. to 700° C. at 5°    C./min to 20° C./min, and cooling to 400° C. to 495° C. at 0.4°    C./min to 0.9° C./min, and cooling to be below 200° C. sequentially,    take it out to obtain the zonal trabecular uni-compartmental plateau    containing zirconium-niobium alloy on oxidation layer.

Further, the inert gas is helium or argon.

The zonal trabecular uni-compartmental plateau containingzirconium-niobium alloy on oxidation layer includes a semi-tibialplateau support 1, a side wall 2 is arranged on the upper surface of thestraight edge of the semi-tibial plateau support 1, and a semielliptical keel plate 3 provided with a long round hole is arranged nearthe side wall of the lower surface of the semi-tibial plateau support,the lower surface of the semi-tibial plateau support and the surface ofthe keel plate 3 are both provided with a bone trabeculae; a front bonetrabeculae 8 and a rear bone trabeculae 9 are arranged on the lowersurface of the semi-tibial plateau support except connecting the keelplate 3; a first partition line 6 of the front bone trabeculae 8 and therear bone trabeculae 9 is perpendicular to the side wall 2 or is formedan angle 4 of 45 °to 70 ° with the side wall 2.

The bone trabeculae arranged on the surface of the keel plate 3comprises an upper bone trabeculae 10 and a lower bone trabeculae 11;the partition line of the upper bone trabeculae and the lower bonetrabeculae is a second partition line 12, and the second partition line12 is located at the lower surface of the top of the long round hole ofthe keel plate 3 or the upper surface of the bottom of the long roundhole of the keel plate 3.

The pore size and porosity of the upper bone trabeculae 10 aresequentially smaller than those of the rear bone trabeculae 9, the frontbone trabeculae 8 and the lower bone trabeculae.

The chemical composition of the zirconium-niobium alloy powder inpercentage by mass is respectively 85.6%-96.5% of Zr, 1.0%-12.5% of Nb,and the rest are unavoidable impurities; where a particle size of thezirconium-niobium alloy powder ranges from 45 to150 µm.

The specific steps for adjusting the temperature in steps 2) and 3) are:increasing the temperature to -120° C. to -80° C. and keeping theconstant temperature for 3 h to 5 h; then increasing the temperature to-40° C. to -20° C. and keeping the constant temperature for 3 h to 5 h;then increasing the temperature to 4° C. to 8° C. and keeping theconstant temperature for 1 h to 3 h and then increasing the temperature.

The first partition line 6 is perpendicular to the side wall 2; anintersection 5 of the first partition line 6 and the side wall 2 dividesthe side wall 2 into a front section 13 and a rear section 14 of theside wall; and the ratio of the front section 13 and the rear section 14is (2-3): 1.

The included angle 4 between the first partition line 6 and the sidewall 2 is 45 ° to 70 °; the intersection 5 of the first partition line 6and side wall 2 is located in the middle of the side wall.

The pore size of the upper bone trabeculae 10 ranges from 351 µm to 450µm, the porosity ranges from 60% to 65%; the pore size of the rear bonetrabeculae 9 ranges from 451 µm to 550 µm, the porosity ranges from 66%to 70%; the pore size of the front bone trabeculae 8 ranges from 551 µmto 650 µm, the porosity ranges from 70% to 75%; the pore size of thelower bone trabeculae 11 ranges from 651 µm to 750 µm, the porosityranges from 76% to 80%.

The thickness of the upper bone trabeculae 10, the rear bone trabeculae9, the front bone trabeculae 8 and the lower bone trabeculae 11 areequal to 1 mm to 2 mm.

The zonal trabecular uni-compartmental tibial plateau containingzirconium-niobium alloy on oxidation layer prepared by the above method.

The present disclosure has the following beneficial effects:

The zonal trabecular uni-compartmental tibial plateau containingzirconium-niobium alloy on oxidation layer in the present disclosureadopts the structure of arranging step distributed bone trabeculaes atthe lower surface of the semi-tibial plateau support and the surface ofthe keel plate so as to reduce the fretting wear of the interfacebetween the prosthesis and the bone, and reduce the stress shieldingeffect of the prosthesis on the bone tissue, homogenize the stress ofthe tibial plateau bone tissue, and improve the initial stability andlong-term stability of the uni-compartmental tibial plateau.

Using integral 3D printing technology, the present disclosure solves theproblem that traditional machining cannot prepare a complex structure,and has high bonding strength between trabeculae and the matrix,therefore it is not easy to fall off, thereby improving the service lifeof the prosthesis.

The zonal trabecular uni-compartmental tibial plateau containingzirconium-niobium alloy on oxidation layer has excellentanti-compression performance. And the compressive yield strength of thesolid part is enhanced, and the plasticity is enhanced.

The zonal trabecular uni-compartmental tibial plateau containingzirconium-niobium alloy on oxidation layer is integrated to realize theexcellent biocompatibility of the osseointegration interface,outstanding bone ingrowth, and a friction interface with super wearresistance and low wear rate.

There is an oxygen-rich layer between the oxidation layer and the matrixof the uni-compartmental tibial plateau prepared by the presentdisclosure. The oxygen-rich layer acts as a transition layer, which canimprove the adhesion between the oxidation layer and the matrix, and canprevent the oxidation layer from falling off. Moreover, the hardness ofthe oxidation layer is high.

The zonal trabecular uni-compartmental tibial plateau containingzirconium-niobium alloy on oxidation layer has low artifacts, littleinterference to nuclear magnetic field, and can be used for nuclearmagnetic field detection.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a structural diagram of the zonal trabecularuni-compartmental tibial plateau containing zirconium-niobium alloy onoxidation layer of the present disclosure.

FIG. 2 shows an axonometric drawing of the zonal trabecularuni-compartmental tibial plateau of the present disclosure.

FIG. 3 shows a front view of the zonal trabecular uni-compartmentaltibial plateau of the present disclosure, wherein the second partitionline 12 passed through the upper surface of the bottom of the long roundhole.

FIG. 4 shows a front view of the zonal trabecular uni-compartmentaltibial plateau of the present disclosure, wherein the second partitionline 12 passed through the lower surface of the top of the long roundhole.

FIG. 5 is a bottom view of the zonal trabecular uni-compartmental tibialplateau of the present disclosure, wherein the included angle betweenthe first partition line 6 and the side wall is 60°, and theintersection is located in the middle of the side wall.

FIG. 6 is a bottom view of the zonal trabecular uni-compartmental tibialplateau of the present disclosure, wherein the included angle betweenthe first partition line 6 is perpendicular to the side wall.

FIG. 7 is the fretting cloud chart showing the interface between theuniform uni-compartmental tibial plateau finite element model and thehost bone tissue finite element model of Control Group 1.

FIG. 8 is the fretting cloud chart showing the interface between theuni-compartmental tibial plateau finite element model and the host bonetissue finite element model of Embodiment 1.

FIG. 9 is the contact pressure cloud chart showing the uniformtrabecular uni-compartmental tibial plateau finite element model ofControl Group 1.

FIG. 10 is the contact pressure cloud chart showing the trabecularuni-compartmental tibial plateau finite element model of Embodiment 1.

FIG. 11 shows the equivalent stress cloud chart of the uniformtrabecular uni-compartmental tibial plateau finite element model ofControl Group 1.

FIG. 12 shows the equivalent stress cloud chart of the trabecularuni-compartmental tibial plateau finite element model of Embodiment 1.

FIG. 13 shows the equivalent stress cloud chart of the finite elementmodel of tibial plateau bone tissue used for the finite element analysisof Control Group 1.

FIG. 14 shows the equivalent stress cloud chart of the finite elementmodel of tibial plateau bone tissue used for the finite element analysisof Embodiment 1.

FIG. 15 shows the metallographic micro structure of the solid part inControl Group 2, wherein A is observed by 50 times magnification; B isobserved by 500 times magnification.

FIG. 16 shows the metallographic microscopic structure of the solid partin Embodiment 1 that has not prepared with step 4) and step 5) in thepreparation method, wherein A is observed by 50 times magnification; Bis observed by 500 times magnification.

FIG. 17 shows SEM images of bone trabeculae in Control Group 2.

FIG. 18 shows SEM images of bone trabeculae in Embodiment 1 that has notbeen prepared with steps 4) and 5) of the preparation method.

FIG. 19 shows the SEM of cross-section between the oxidation layer andthe matrix in Embodiment 1.

FIG. 20 shows the XRD curve of the oxidation layer surface in Embodiment1.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The present disclosure will be further described below with the drawingsand embodiments.

Embodiment 1

The preparation method of the zonal trabecular uni-compartmental tibialplateau containing zirconium-niobium alloy on oxidation layer includesthe following steps:

1) Using zirconium-niobium alloy powder as a raw material, the firstintermediate product of the zonal trabecular uni-compartmental tibialplateau containing zirconium-niobium alloy on oxidation layer isintegrally formed by 3D printing, putting the first intermediate productinto a Sinter-HIP furnace, heating to 1250° C. under helium gasprotection, and placing at a constant pressure of 180 MPa for 3 h, andreducing to a normal pressure, cooling to below 200° C. with thefurnace, taking it out, and obtaining a second intermediate product;

2) Putting the second intermediate product into a programmed thermostat,cooling to -80°Cat a rate of 1° C./min, keeping it at a constanttemperature for 10 h, and taking it out of the programmed thermostat;and putting it into a liquid nitrogen for 16 h, and adjusting thetemperature to a room temperature so as to obtain a third intermediateproduct;

3) Putting the third intermediate product in a programmed thermostat,cooling to -80° C. at a rate of 1° C./min, and placing it at a constanttemperature for 10 h, taking it out of the programmed thermostat, andputting it into the liquid nitrogen for 16 h, and adjusting thetemperature to room temperature so as to obtain a fourth intermediateproduct.

The specific steps for adjusting the temperature in steps 2) and 3) are:increase the temperature to -120° C. and keep the constant temperaturefor 5 h, then increase the temperature to -40° C. and keep the constanttemperature for 5 h, then increase the temperature to 4° C. and keep theconstant temperature for 3 h and then increase the temperature.

4) The fourth intermediate product is machined, finished, polished,cleaned and dried to obtain a fifth intermediate product. The uppersurface roughness of the fifth intermediate semi-tibial plateau supportis Ra=0.012 µm.

5) Putting the fifth intermediate product into a tube furnace,introducing the normal-pressure helium gas containing 5% of oxygen inpercentage by mass, heating to 500° C. at 5° C./min, and coolingto400°Cat 0.4° C./min, and cooling to be below 200° C. sequentially,take it out to obtain the zonal trabecular uni-compartmental plateaucontaining zirconium-niobium alloy on oxidation layer.

The structure of the zonal trabecular uni-compartmental plateaucontaining zirconium-niobium alloy on oxidation layer is the same as itsfirst intermediate product, second intermediate product, thirdintermediate product, fourth intermediate product, and fifthintermediate product.

The chemical composition of the zirconium-niobium alloy powder isrespectively 85.6% of Zr, 12.5% of Nb by mass percentage, and the restare unavoidable impurities. The zirconium-niobium alloy powder has aparticle size of 45-150 µm and is purchased from Xi’an Sailong MetalMaterials Co., Ltd.

As shown in FIGS. 1-2 , the structure of the above-mentioned zonaltrabecular uni-compartmental plateau containing zirconium-niobium alloyon oxidation layer includes a semi-tibial plateau support 1, a side wall2 is arranged on the upper surface of the straight edge of thesemi-tibial plateau support 1, and a semi elliptical keel plate 3provided with a long round hole is arranged near the side wall of thelower surface of the semi-tibial plateau support 1, the lower surface ofthe semi-tibial plateau support and the surface of the keel plate 3 areboth provided with a bone trabeculae; a front bone trabeculae 8 and arear bone trabeculae 9 are arranged on the lower surface of thesemi-tibial plateau support except connecting the keel plate 3; as shownin FIG. 6 , a first partition line 6 of the front bone trabeculae 8 andthe rear bone trabeculae 9 is perpendicular to the side wall 2. Theintersection 5 of the first partition line 6 and the side wall 2 dividesthe side wall 2 into a front section 13 and a rear section 14 of theside wall; and the ratio of the front section 13 and the rear section 14is 2: 1, and the ratio can also be 3:1.

As shown in FIG. 3 , the bone trabeculae arranged on the surface of thekeel plate 3 comprises an upper bone trabeculae 10 and a lower bonetrabeculae 11; the partition line of the upper bone trabeculae and thelower bone trabeculae is a second partition line 12, and the secondpartition line 12 is located at the lower surface of the top of the longround hole of the keel plate 3.

The pore size of the upper bone trabeculae 10 is 400 µm, the porosity is63%.

The pore size of the rear bone trabeculae 9 is 500 µm, the porosity is68%.

The pore size of the front bone trabeculae 8 is 600 µm, the porosity is73%;

The pore size of the lower bone trabeculae 11 is 700 µm, the porosity is78%.

The thickness of the upper bone trabeculae 10, the rear bone trabeculae9, the front bone trabeculae 8 and the lower bone trabeculae 11 areequal to 1.5 mm.

Embodiment 2

The preparation method of the zonal trabecular uni-compartmental tibialplateau containing zirconium-niobium alloy on oxidation layer includesthe following steps:

-   1) Using zirconium-niobium alloy powder as a raw material, the first    intermediate product of the zonal trabecular uni-compartmental    tibial plateau containing zirconium-niobium alloy on oxidation layer    is integrally formed by 3D printing, putting the first intermediate    product into a Sinter-HIP furnace, heating to 1325° C. under helium    gas protection, and placing at a constant pressure of 160 MPa for 2    h, and reducing to a normal pressure, cooling to below 200° C. with    the furnace, taking it out, and obtaining a second intermediate    product;-   2) Putting the second intermediate product into a programmed    thermostat, cooling to -100°Cat a rate of 1° C./min, keeping it at a    constant temperature for 7 h, and taking it out of the programmed    thermostat; and putting it into a liquid nitrogen for 24 h, and    adjusting the temperature to a room temperature so as to obtain a    third intermediate product;-   3) Putting the third intermediate product in a programmed    thermostat, cooling to -100° C. at a rate of 1° C./min, and placing    it at a constant temperature for 7 h, taking it out of the    programmed thermostat, and putting it into the liquid nitrogen for    24 h, and adjusting the temperature to room temperature so as to    obtain a fourth intermediate product.

The specific steps for adjusting the temperature in steps 2) and 3) are:increase the temperature to -100° C. and keep the constant temperaturefor 4 h, then increase the temperature to -30° C. and keep the constanttemperature for 4 h, then increase the temperature to 6° C. and keep theconstant temperature for 2 h and then increase the temperature.

4) The fourth intermediate product is machined, finished, polished,cleaned and dried to obtain a fifth intermediate product. The uppersurface roughness of the fifth intermediate semi-tibial plateau supportis Ra=0.035 µm.

5) Putting the fifth intermediate product into a tube furnace,introducing the normal-pressure helium gas containing 10% of oxygen inpercentage by mass, heating to 600° C. at 15° C./min, and cooling to450°Cat 0.7° C./min, and cooling to be below 200° C. sequentially, takeit out to obtain the zonal trabecular uni-compartmental plateaucontaining zirconium-niobium alloy on oxidation layer.

The structure of the zonal trabecular uni-compartmental plateaucontaining zirconium-niobium alloy on oxidation layer is the same as itsfirst intermediate product, second intermediate product, thirdintermediate product, fourth intermediate product, and fifthintermediate product.

The structure of the above-mentioned zonal trabecular uni-compartmentalplateau containing zirconium-niobium alloy on oxidation layer includes asemi-tibial plateau support 1, a side wall 2 is arranged on the uppersurface of the straight edge of the semi-tibial plateau support 1, and asemi elliptical keel plate 3 provided with a long round hole is arrangednear the side wall of the lower surface of the semi-tibial plateausupport 1, the lower surface of the semi-tibial plateau support and thesurface of the keel plate 3 are both provided with a bone trabeculae; afront bone trabeculae 8 and a rear bone trabeculae 9 are arranged on thelower surface of the semi-tibial plateau support except connecting thekeel plate 3; as shown in FIG. 5 , a first partition line 6 of the frontbone trabeculae 8 and the rear bone trabeculae 9 is formed an angle 4 of45 °with the side wall 2; and the intersection 5 of the first partitionline 6 and the side wall 2 is in the middle of the side wall.

As shown in FIG. 4 , the bone trabeculae arranged on the surface of thekeel plate 3 comprises an upper bone trabeculae 10 and a lower bonetrabeculae 11; the partition line of the upper bone trabeculae and thelower bone trabeculae is a second partition line 12, and the secondpartition line 12 is located at the upper surface of the bottom of thelong round hole of the keel plate 3.

The chemical composition of the zirconium-niobium alloy powder isrespectively 93.4% of Zr, 5.1% of Nb by mass percentage, and the restare unavoidable impurities. The zirconium-niobium alloy powder has aparticle size of 45-150 µm and is purchased from Xi’an Sailong MetalMaterials Co., Ltd.

The pore size of the upper bone trabeculae 10 is 351 µm, the porosity is60%.

The pore size of the rear bone trabeculae 9 is 451 µm, the porosity is66%.

The pore size of the front bone trabeculae 8 is 551 µm, the porosity is70%;

The pore size of the lower bone trabeculae 11 is 651 µm, the porosity is76%.

The thickness of the upper bone trabeculae 10, the rear bone trabeculae9, the front bone trabeculae 8 and the lower bone trabeculae 11 areequal to 1 mm.

Embodiment 3

The preparation method of the zonal trabecular uni-compartmental tibialplateau containing zirconium-niobium alloy on oxidation layer includesthe following steps:

-   1) Using zirconium-niobium alloy powder as a raw material, the first    intermediate product of the zonal trabecular uni-compartmental    tibial plateau containing zirconium-niobium alloy on oxidation layer    is integrally formed by 3D printing, putting the first intermediate    product into a Sinter-HIP furnace, heating to 1400° C. under argon    gas protection, and placing at a constant pressure of 140 MPa for 1    h, and reducing to a normal pressure, cooling to below 200° C. with    the furnace, taking it out, and obtaining a second intermediate    product;-   2) Putting the second intermediate product into a programmed    thermostat, cooling to -120°Cat a rate of 1° C./min, keeping it at a    constant temperature for 5 h, and taking it out of the programmed    thermostat; and putting it into a liquid nitrogen for 36 h, and    adjusting the temperature to a room temperature so as to obtain a    third intermediate product;-   3) Putting the third intermediate product in a programmed    thermostat, cooling to -120° C. at a rate of 1° C./min, and placing    it at a constant temperature for 5 h, taking it out of the    programmed thermostat, and putting it into the liquid nitrogen for    36 h, and adjusting the temperature to room temperature so as to    obtain a fourth intermediate product.

The specific steps for adjusting the temperature in steps 2) and 3) are:increase the temperature to -80° C. and keep the constant temperaturefor 3 h, then increase the temperature to -20° C. and keep the constanttemperature for 3 h, then increase the temperature to 8° C. and keep theconstant temperature for 1 h and then increase the temperature.

4) The fourth intermediate product is machined, finished, polished,cleaned and dried to obtain a fifth intermediate product. The uppersurface roughness of the fifth intermediate semi-tibial plateau supportis Ra=0.050 µm.

5) Putting the fifth intermediate product into a tube furnace,introducing the normal-pressure argon gas containing 15% of oxygen inpercentage by mass, heating to 700° C. at 20° C./min, and cooling to495°Cat 0.9° C./min, and cooling to be below 200° C. sequentially, takeit out to obtain the zonal trabecular uni-compartmental plateaucontaining zirconium-niobium alloy on oxidation layer.

The structure of the above-mentioned zonal trabecular uni-compartmentalplateau containing zirconium-niobium alloy on oxidation layer includes asemi-tibial plateau support 1, a side wall 2 is arranged on the uppersurface of the straight edge of the semi-tibial plateau support 1, and asemi elliptical keel plate 3 provided with a long round hole is arrangednear the side wall of the lower surface of the semi-tibial plateausupport 1, the lower surface of the semi-tibial plateau support and thesurface of the keel plate 3 are both provided with a bone trabeculae; afront bone trabeculae 8 and a rear bone trabeculae 9 are arranged on thelower surface of the semi-tibial plateau support except connecting thekeel plate 3; a first partition line 6 of the front bone trabeculae 8and the rear bone trabeculae 9 is formed an angle 4 of 70° with the sidewall 2; and the intersection 5 of the first partition line 6 and theside wall 2 is in the middle of the side wall.

As shown in FIG. 3 , the bone trabeculae arranged on the surface of thekeel plate 3 comprises an upper bone trabeculae 10 and a lower bonetrabeculae 11; the partition line of the upper bone trabeculae and thelower bone trabeculae is a second partition line 12, and the secondpartition line 12 is located at the lower surface of the top of the longround hole of the keel plate 3.

The chemical composition of the zirconium-niobium alloy powder isrespectively 96.5% of Zr, 1% of Nb by mass percentage, and the rest areunavoidable impurities. The zirconium-niobium alloy powder has aparticle size of 45-150 µm and is purchased from Xi’an Sailong MetalMaterials Co., Ltd.

The pore size of the upper bone trabeculae 10 is 450 µm, the porosity is65%.

The pore size of the rear bone trabeculae 9 is 550 µm, the porosity is70%.

The pore size of the front bone trabeculae 8 is 650 µm, the porosity is75%;

The pore size of the lower bone trabeculae 11 is 750 µm, the porosity is80%.

The thickness of the upper bone trabeculae 10, the rear bone trabeculae9, the front bone trabeculae 8 and the lower bone trabeculae 11 areequal to 2 mm.

Control Group 1

The structure of an uniform trabecular uni-compartmental tibial plateauis similar to that of the Embodiment 1, the different structure betweenthe uniform trabecular uni-compartmental tibial plateau and theEmbodiment 1 are as follows:

The thickness of the upper bone trabeculae 10, the lower bone trabeculae11, the front bone trabeculae 8 and the rear bone trabeculae 9 are asame kind of the bone trabeculae with a pore size of 500 µm, a porosityof 68%, and a trabecular thickness of 1.5 mm.

Control Group 2

Using zirconium-niobium alloy powder as Embodiment 1 as a raw material,conducting a 3D printing for one-piece molding, and obtaining zonaltrabecular uni-compartmental tibial plateau which structure is same asthat of the Embodiment 1.

Experiment Verification

The reliable biological fixation of prosthesis bone interface mainlydepends on the initial stability of prosthesis fixation. Excessiverelative movement between prosthesis and bone interface will inhibit theprocess of bone integration. Studies have shown that when the frettingat the interface of prosthesis and bone exceeds 50 to 150 µm, a largeamount of fibrous tissue will be formed at the bone interface, whichwill reduce the fixation strength of the prosthesis and eventually leadto prosthesis loosening. The finite element model of Control Group 1 andEmbodiment 1 and the simplified cancellous bone partitioning model ofthe tibial plateau were analyzed by finite element analysis to obtainthe fretting cloud map, as shown in FIGS. 7-8 , compared with theuniform trabecular tibial plateau of Control Group 1, the maximumfretting value at the interface between the zonal trabecularuni-compartmental tibial plateau finite element model and the tibialplateau bone tissue finite element model in Embodiment 1 is 4.50 µm,decreased by 43%, suggesting that the present disclosure can obtainsmall fretting and has excellent initial stability.

The finite element model of Control Group 1 and Embodiment 1 and thesimplified cancellous bone partitioning model of the tibial plateau wereanalyzed by finite element analysis to obtain the contact pressure cloudchart (as shown in FIGS. 9-10 ) and equivalent stress cloud chart (asshown in FIGS. 11-14 ). Compared with the uniform trabecular tibialplateau of Control Group 1, the finite element model of theuni-compartmental tibial plateau in Embodiment 1 has more uniformcontact pressure, suggesting that the bone growth performance isuniform. The maximum equivalent stress of the of the finite elementmodel of the uni-compartmental tibial plateau in Embodiment 1 is 2.5MPa, which is reduced by about 40%; and the maximum equivalent stress ofthe corresponding tibial plateau bone tissue finite element model is1.28Mpa, which is increased by about 4%, suggesting that theuni-compartmental tibial plateau prepared by the present disclosurereduce the stress shielding effect and have excellent bone ingrowth. Theresult showed that the uni-compartmental tibial plateau prepared by thepresent disclosure have excellent and uniform bone ingrowth performance,which can avoid prosthesis loosening caused by osteoporosis afterlong-term prosthesis implantation, and can obtain long-term stability.

The results of the finite element analysis show that the fretting cloudchart, contact pressure cloud chart and equivalent stress cloud chart ofEmbodiments 2 and 3 are similar to those of Embodiment 1.

A solid part in the control group 2 and a solid part of the embodiment 1that has not been prepared with step 4) and 5) were observed andanalyzed by an inverted scanning electron microscope (Axio Vert.A1,Zeiss, Germany). The results were shown in FIGS. 15-16 . In themetallographic photos of the Control Group 2, small α martensite can beobserved. The structure is small, easy for stress concentration, and theplasticity is poor. In the metallograph of Embodiment 1, α phase can beobserved, basket net structure, grain refinement. The results indicatedthat the matrix (without oxidation layer) of the uni-compartmentaltibial plateau prepared by the present disclosure has excellent strengthand plasticity.

As shown in FIGS. 17-18 , the trabecular part of the control group 2 andthe trabecular part of the embodiment 1 that has not been prepared withstep 4) and 5) were observed and analyzed by scanning electronmicroscopy (Crossbeam340/550, Zeiss, Germany). Compared with the controlgroup 2, the zirconium-niobium alloy powder of the trabecular part ofthe embodiment 1 was further sintered, suggesting that the overallperformance of the bone trabeculae was improved.

A physical compression test piece (size: 8*8*10 mm³) that has not beenprepared with step 4) and 5) in the preparation method in the embodiment1 and a physical compression test piece (size: 8*8*10 mm³) in thecontrol group 2 were subjected to a compression performance test by anelectronic universal testing machine (UTM5105, Shenzhen SUNS TechnologyCo., Ltd., and China). There were 5 physical compression test piecesrespectively in the embodiment 1 and the control group 2. Results wereshown in Table 1. The compressive yield strength of embodiment 1 is546.72 MPa, better than that of Control Group 2 (P<0.05), suggestingthat the solid part prepared by the present disclosure has excellentanti-compression performance.

TABLE 1 Anti-compression experiment results of the solid specimens ofControl Group 2 and Embodiment 1 (x± s, n=5, *P<0.05, compared withControl Group 2) Group Cross-sectional Area (mm²) Yield Load (kN) YieldStrength (MPa) Embodiment 1 64 34.99±4.04* 546.72±63.19* Control Group 264 23.59±2.30 368.63±35.92

A bone trabeculae compression specimens with pore size of 600 µm andporosity of 73% of the Control Group 2 and the bone trabeculaecompression specimens with pore size of 600 µm and porosity of 73% ofEmbodiment 1 (specimen size: 8*8*10 mm³) that has not been prepared withstep 4) and step 5) of the above-mentioned preparation method, weresubjected to a compression test by the electronic universal testingmachine (UTM5105, Shenzhen SUNS Technology Co., Ltd., and China). Bonetrabeculae compression specimens of the Control Group 2 and theEmbodiment 1 were 5 pieces each. The results are shown in Table 2. Thecompressive yield strength of Embodiment 1 is 17.92 MPa, significantlybetter than that of Control Group 2 (P<0.05), suggesting that the bonetrabecular part of the tibial plateau prepared by the present disclosurehas excellent anti-compression performance.

TABLE 2 Anti-compression experiment results of the bone trabecularspecimens of Control Group 2 and Embodiment 1 (x± s, n=5, *P<0.05,compared with Control Group 2) Group Cross-sectional Area (mm²) YieldLoad (N) Yield Strength (MPa) Embodiment 1 64 1147.03±87.15* 17.92±1.36*Control Group 2 64 894.86±98.12 13.98±1.53

The cross-section of the matrix and oxidation layer of thezirconium-niobium alloy of Embodiment 1 was observed by scanningelectron microscopy (Crossbeam340/550, Zeiss, Germany) (see FIG. 19 ).The cross sections of the matrix and oxidation layer of thezirconium-niobium alloy in Embodiments 2 and 3 were observed. Theoxidation layer thickness were 10.3 µm, 17.2 µm and 20.6 µm,respectively. There was an oxygen-rich layer between the oxidation layerand the matrix of the zirconium-niobium alloy to enhance the bondingforce between the matrix and oxidation layer of zirconium-niobium alloy.

XRD (D8DISCOVER, Bruker, Germany) analyzed the oxidation layer of thezonal trabecular uni-compartmental tibial plateau of Embodiment 1 (asshown in FIG. 20 ). The oxidation layer contained monoclinic phasezirconia and tetragonal phase zirconia.

The microhardness measurement on the zonal trabecular uni-compartmentaltibial plateau of Embodiments 1-3 was determined by a microhardnesstester (MHVS-1000 PLUS, Shanghai Aolongxingdi Testing Equipment Co.,Ltd., China), in which the load was 0.05 kg, the load time of thespecimens was 20 s, and 8 points were taken for each specimen. Theaverage hardness values measured in Embodiments 1-3 were 1948.6Hv,1923.7Hv, and 1967.2Hv, suggesting that the oxidation layer in the zonaltrabecular uni-compartmental tibial plateau of the present disclosurehas high hardness.

Experiments have proved that the zirconium-niobium alloy powder bondingdegree, compressive properties, solid part of the compressiveproperties, metallographic structure, the crystal structure, thicknessand hardness of the oxidation layer for the zonal trabecularuni-compartmental tibial plateau prepared in Embodiments 2 and 3, aresimilar to that prepared in Embodiment 1.

1. A preparation method of the zonal trabecular uni-compartmental tibialplateau containing zirconium-niobium alloy on oxidation layer, includingthe following steps: 1) using zirconium-niobium alloy powder as a rawmaterial, conducting a 3D printing for one-piece molding, and obtaininga first intermediate product of the zonal trabecular uni-compartmentaltibial plateau containing zirconium-niobium alloy on oxidation layer,putting the first intermediate product into a Sinter-HIP furnace,heating to 1250° C.-1400° C. under inert gas protection, and placing ata constant pressure of 140 MPa to 180 MPa for 1 h to 3 h, and reducingto a normal pressure, cooling to below 200° C. with the furnace, takingit out, and obtaining a second intermediate product; 2) putting thesecond intermediate product into a programmed thermostat, cooling to-80° C. to -120° C. at a rate of 1° C./min, keeping it at a constanttemperature for 5 h to10 h, and taking it out of the programmedthermostat; and putting it into a liquid nitrogen for 16 h to 36 h, andadjusting the temperature to a room temperature so as to obtain a thirdintermediate product; 3) putting the third intermediate product in aprogrammed thermostat, cooling to -80° C. to -120° C. at a rate of 1°C./min, and placing it at a constant temperature for 5 h to10 h, takingit out of the programmed thermostat, and putting it into the liquidnitrogen for 16 h to 36 h, and adjusting the temperature to roomtemperature so as to obtain a fourth intermediate product; 4) machining,finishing, polishing, cleaning, and drying the fourth intermediateproduct, and obtaining a fifth intermediate product, where the uppersurface roughness of the fifth intermediate semi-tibial plateau supportis Ra≤0.050 µm; 5) putting the fifth intermediate product into a tubefurnace, introducing the normal-pressure inert gas containing 5% to 15%of oxygen in percentage by mass, heating to 500° C. to 700° C. at 5°C./min to 20° C./min, and cooling to 400° C. to 495° C. at 0.4° C./minto 0.9° C./min, and cooling to be below 200° C. sequentially, take itout to obtain the zonal trabecular uni-compartmental plateau containingzirconium-niobium alloy on oxidation layer. wherein, the inert gas ishelium or argon; the zonal trabecular uni-compartmental plateaucontaining zirconium-niobium alloy on oxidation layer includes asemi-tibial plateau support (1), a side wall (2) is arranged on theupper surface of the straight edge of the semi-tibial plateau support(1), and a semi elliptical keel plate (3) provided with a long roundhole is arranged near the side wall of the lower surface of thesemi-tibial plateau support, the lower surface of the semi-tibialplateau support (1) and the surface of the keel plate (3) are bothprovided with a bone trabeculae; a front bone trabeculae (8) and a rearbone trabeculae (9) are arranged on the lower surface of the semi-tibialplateau support (1) except connecting the keel plate (3); a firstpartition line (6) of the front bone trabeculae (8) and the rear bonetrabeculae (9) is perpendicular to the side wall (2) or is formed anangle (4) of 45 °to 70 ° with the side wall (2); the bone trabeculaearranged on the surface of the keel plate (3) comprises an upper bonetrabeculae (10) and a lower bone trabeculae (11); the partition line ofthe upper bone trabeculae and the lower bone trabeculae is a secondpartition line (12), and the second partition line (12) is located atthe lower surface of the top of the long round hole of the keel plate(3) or the upper surface of the bottom of the long round hole of thekeel plate (3); the pore size and porosity of the upper bone trabeculae(10) are sequentially smaller than those of the rear bone trabeculae,the front bone trabeculae and the lower bone trabeculae.
 2. Thepreparation method of the zonal trabecular uni-compartmental tibialplateau containing zirconium-niobium alloy on oxidation layer accordingto claim 1, wherein the chemical composition of the zirconium-niobiumalloy powder in percentage by mass is respectively 85.6%-96.5% of Zr,1.0%-12.5% of Nb, and the rest are unavoidable impurities; where aparticle size of the zirconium-niobium alloy powder ranges from 45 to150 µm.
 3. The preparation method of the zonal trabecularuni-compartmental tibial plateau containing zirconium-niobium alloy onoxidation layer according to claim 1, wherein the specific steps foradjusting the temperature in steps 2) and 3) are: increasing thetemperature to -120° C. to -80° C. and keeping the constant temperaturefor 3 h to 5 h; then increasing the temperature to -40° C. to -20° C.and keeping the constant temperature for 3 h to 5 h; then increasing thetemperature to 4° C. to 8° C. and keeping the constant temperature for 1h to 3 h and then increasing the temperature.
 4. The preparation methodof the zonal trabecular uni-compartmental tibial plateau containingzirconium-niobium alloy on oxidation layer according to claim 1, whereinthe first partition line (6) is perpendicular to the side wall (2); anintersection (5) of the first partition line (6) and the side wall (2)divides the side wall (2) into a front section (13) and a rear section(14) of the side wall; and the ratio of the front section (13) and therear section (14) is (2-3):
 1. 5. The preparation method of the zonaltrabecular uni-compartmental tibial plateau containing zirconium-niobiumalloy on oxidation layer according to claim 1, wherein the includedangle (4) between the first partition line (6) and the side wall (2) is45 ° to 70 °; the intersection (5) of the first partition line (6) andside wall (2) is located in the middle of the side wall.
 6. Thepreparation method of the zonal trabecular uni-compartmental tibialplateau containing zirconium-niobium alloy on oxidation layer accordingto claim 1, wherein the pore size of the upper bone trabeculae (10)ranges from 351 µm to 450 µm, the porosity ranges from 60% to 65%; thepore size of the rear bone trabeculae (9) ranges from 451 µm to 550 µm,the porosity ranges from 66% to 70%; the pore size of the front bonetrabeculae (8) ranges from 551 µm to 650 µm, the porosity ranges from70% to 75%; the pore size of the lower bone trabeculae (11) ranges from651 µm to 750 µm, the porosity ranges from 76% to 80%; the thickness ofthe upper bone trabeculae (10), the rear bone trabeculae (9), the frontbone trabeculae (8) and the lower bone trabeculae (11) are equal to 1 mmto 2 mm.
 7. A zonal trabecular uni-compartmental tibial plateaucontaining zirconium-niobium alloy on oxidation layer prepared by thepreparation method of the zonal trabecular uni-compartmental tibialplateau containing zirconium-niobium alloy on oxidation layer accordingto claim
 1. 8. The zonal trabecular uni-compartmental tibial plateau ofclaim 7, the chemical composition of the zirconium-niobium alloy powderin percentage by mass is respectively 85.6%-96.5% of Zr, 1.0%-12.5% ofNb, and the rest are unavoidable impurities; where the particle size ofthe zirconium-niobium alloy powder ranges from 45 to 150 µm.
 9. Thezonal trabecular uni-compartmental tibial plateau of claim 7, whereinthe specific steps for adjusting the temperature in steps 2) and 3) are:increasing the temperature to -120° C. to -80° C. and keeping theconstant temperature for 3 h to 5 h; then increasing the temperature to-40° C. to -20° C. and keeping the constant temperature for 3 h to 5 h;then increasing the temperature to 4° C. to 8° C. and keeping theconstant temperature for 1 h to 3 h and then increasing the temperature.10. The zonal trabecular uni-compartmental tibial plateau of claim 7,wherein the first partition line (6) is perpendicular to the side wall(2); an intersection (5) of the first partition line (6) and the sidewall (2) divides the side wall (2) into the front section (13) and therear section (14) of the side wall; and the ratio of the front section(13) and the rear section (14) is (2-3):
 1. 11. The zonal trabecularuni-compartmental tibial plateau of claim 7, wherein the included angle(4) between the first partition line (6) and the side wall (2) is 45 °to 70 °; the intersection (5) of the first partition line (6) and sidewall (2) is located in the middle of the side wall.
 12. The zonaltrabecular uni-compartmental tibial plateau of claim 7, wherein theincluded angle (4) between the first partition line (6) and the sidewall (2) is 45 ° to 70°; the intersection (5) of the first partitionline (6) and side wall (2) is located in the middle of the side wall.13. The zonal trabecular uni-compartmental tibial plateau of claim 7,wherein the pore size of the upper bone trabeculae (10) ranges from 351µm to 450 µm, the porosity ranges from 60% to 65%; the pore size of therear bone trabeculae (9) ranges from 451 µm to 550 µm, the porosityranges from 66% to 70%; the pore size of the front bone trabeculae (8)ranges from 551 µm to 650 µm, the porosity ranges from 70% to 75%; thepore size of the lower bone trabeculae (11) ranges from 651 µm to 750µm, the porosity ranges from 76% to 80%; the thickness of the upper bonetrabeculae (10), the rear bone trabeculae (9), the front bone trabeculae(8) and the lower bone trabeculae (11) are equal to 1 mm to 2 mm.